Confession time. I usually
don't expect much from headphone
manufacturers when it comes to building their own amplifiers. I've never
particularly liked any of the amplification offerings from companies like
Beyerdynamic, HIFIMAN or Fostex. At best, I guess I was somewhat indifferent to
the original Sennheiser HDVD 800. I felt it sounded good enough, but I also
didn't feel like the sound-per-dollar value or absolute performance was
particularly worthy of recommendation over similarly priced amplifiers, in most
cases.

So I approached Sennheiser's new flagship DAC/amp, the HDV
820 ($2399), with a bit of skepticism. On one hand, you have that fairly
checkered history of amps from headphone manufacturers. On the other, you have a
pretty convincing piece of evidence for the other side of the argument: the last
DAC/amp Sennheiser designed was attached to the Sennheiser HE-1 ($55,000),
claimed by some to be the world's best sounding headphone system.

To my delight, it turns out the new Sennheiser HDV 820 is the
genuine article. Not just an adequate performer or a synergy master specifically
for the HD800 and HD800S, but a truly exceptional piece of equipment. So what
makes this one succeed where others have failed? Let's take a look.

A Jack of All... Or Most
TradesThe first thing the HDV 820 has going for it is versatility.
Lots and lots of versatility. It has all of the standard digital inputs: USB,
optical and coaxial; plus balanced and unbalanced analog inputs. And it has more
than its fair share of outputs: 6.3mm unbalanced, 4-pin balanced, (two) 4.4mm
balanced Pentaconn connectors, and 3-pin balanced outs on the rear side allowing
the HDV 820 to be used as a preamp for active monitors.

The second thing it has is power, and lots of it. Per
Sennheiser's Axel Grell, it puts out a very clean 2.76 Watts of power at 32
Ohms, 2.5 Watts at 50 Ohms and 960mW at 300 Ohms. While 2.5W at 50 Ohms may not
sound particularly jaw-dropping to the power-hungry planar crowd, let me assure
you, this amp has more than enough current on tap to get the job done. It drove
the ever-demanding Abyss AB-1266 (86dB sensitivity) fairly well, and had
absolutely no problems driving the slightly-less-demanding ZMF Ori and HIFIMAN
HE500.

On the opposite end of the sensitivity spectrum, HDV 820 was a
bit on the strong side for ultra-sensitive in-ears and I heard a bit of hum when
I tried it with the Campfire Vega (reviewed
here). Unfortunately, I was not able to test IEMs with a balanced connector,
so I can't comment on the noise drop with the benefit of common mode noise
cancellation. My full-sized sensitive headphones performed well however,
including my Grados and my modded Denon D2000, which is quite sensitive at
106dB/mW and 25 Ohm impedance. The background was nice and black on the
hyper-sensitive Denon, and the HDV 820 was able to milk out one of the best
performances I've heard from it in a while.

For the digital section, Sennheiser has chosen to employ the
ESS Sabre ES9018 chip. Sabre DACs have taken a fair share of flack – and much
of it is well deserved – but keep in mind, the sound of a DAC is really about
2% chip and 98% implementation. While the ES9018 may not be the world's most
popular chip among personal audio enthusiasts, I believe most of that is really
due to its frequent implementation in poorly designed DACs. It's actually
implemented pretty well here. There was none of the trademark "Sabre Glare"
that you often find in many ES9018-based DACs.

That being said, I like the amplifier quite a bit more than I
like the DAC for entirely different reasons, which I'll get into in a minute.
The DAC, isn't terrible by any means (and it actually reminded me of a DAC
that I like quite a bit), it's just that the amplifier outclasses it and
scales up significantly with a better DAC. So, on that note, I'm going to
examine them both separately, so you'll know what to expect and can make an
informed buying decision. We'll start by taking a look at the amplifier
section.

Okay Guys, Where Did You Hide
The Tubes?The HDV 820's amplifier is really one sweet-sounding piece
of kit. The tone runs a little on the warm side of neutral, which really brings
out the best from the somewhat dry-ish and by-the-book HD800.

In some ways the HDV 820's tonality reminds me a little of
the slightly lush, but hyper-detailed presentation of the now discontinued
Cavalli Liquid Gold, which is one of my all-time favorite pairings with the
HD800. It's not an exact match, but bears some tonal similarity to the
legendary LAu in its ability to even out the HD800 and make it sound stunningly
realistic. It's not quite as expansive and maybe a pinch behind in
transparency, but for $1600 less, it's close and it certainly isn't lacking
in either of those aspects.

Treble is held under a firm grip of control and is buttery
smooth on the occasionally unforgiving HD800. In over a month with the
amplifier, I can't recall cringing at a sibilant treble spike. It's not
going to magically make the HD800 a top-choice for k-pop all of a sudden, but it
certainly expands the HD800's range of enjoyable music quite considerably.
There is ample air up top, which gives the music a free and easy feel, though
the amplifier is perhaps not as supremely airy and open sounding as some others
like the Rogue Audio RH-5 (reviewed
here), which is elite in that regard.

The midrange is where this amplifier truly shines, in my
opinion, delivering superb musicality that is usually only reserved for tube
amps. I found the HDV 820 really excelled with rock music, delivering gobs of
soul that had me feeling very connected to the music. The upper midrange is a
little warmed and mellowed out – a trait that I often describe as "speaker-like", while the lower mids feel extra full and robust.
It's a
warm and sweet sound, and when you've got a good album rolling, this is a very
hard amp to walk away from. I was absolutely glued to my chair after I popped on
Steely Dan's seminal classic "Aja", and soon found myself re-prioritizing
my evening just so I could give it a second spin.

The bass is also warm, with solid (but not elite) rumble and
impact. It is certainly enough to be satisfying and I never really found myself
needing more. The low end also has a bit of that aforementioned tubeyness to it.
Low frequency notes come off as slightly more rounded and natural than punchy
and abrupt – which is not to say it is loose – there is actually a ton of
information down there. As a bass player myself, this type of sound comes across
to me as more "live" than "studio-like". I don't necessarily feel one
way is better than the other, they are just different.

To elaborate a little further, bass in a live setting
reverberates off of just about every surface in a given room, which often adds a
layer of harmonic richness to the sound that is not always present in solid
state amplifiers. Tubes usually do a better job of duplicating those harmonic
overtones, which to my ears, generally makes them sound a tiny bit more
transparent. I feel like the "tubeyness" of the HDV 820 also captures a lot
of that natural low-end detail too. Bass was far from the "one-note"
variety, and I even picked up a few nuances I'd never noticed before, even in
really good gear.

The inner detail of the amplifier is quite strong, and it
really showed its stuff when paired with the ultra-detailed Chord Hugo 2 (reviewed
here). But what really impressed me was the level of ambient micro detail.
Tiny decay trails off the end of instruments revealed the size and shape of the
recording space with a stunning level of precision. Listening to Adele's "Hello" was a revelation. The performance was super intimate, and I felt
like I was right there in the room for the recording. Each additional vocal
harmony that was introduced was well-separated, highly-detailed and impressively
appreciable as an individual element.

Now we've come to perhaps my favorite part of the HDV 820,
the soundstage and imaging. You had to imagine that an amplifier that is
designed to be paired with the legendary HD800 would do this well, and the HDV
820 really knocks it out of the park.

To me, the most impressive part of the soundscape
isn't the
size, it is the immersion it offers. The stage isn't as massive as the
recently reviewed Rogue Audio RH-5 or a pair of Questyle CMA800R's running in
dual mono. Those amplifiers offer truly elite width. However, what the HDV 820
does in terms of enveloping you in the sound is, in my opinion, every bit as
impressive. Listening to the HDV makes it feel like you are inside the music,
creating a deeply emotional listening experience.

How does it do this? The answer lies in the excellent depth
layering – without a doubt, some of the best I've heard from a pure solid
state. Listening to Bohemian Rhapsody in DSD on the HDV 820 via the Chord Hugo 2
was stunning. I was literally sitting there with my jaw hanging wide open as the
multi-layered vocals unfolded at pinpoint spots front-to-back on the stage. Not
surprising that this was designed by the same folks who designed the HE-1 –
even though it is nowhere near as expansive or multi-layered as the HE-1, it
brings a little tiny taste of it's field depth magic at a price that's much
more attainable for the rest of us.

As amplifiers go, I would take no issue with recommending the
HDV 820 as an amplifier alone at its full retail price of $2395. To my ears it
is an outstanding piece and absolutely worthy of its substantial price tag. But
this isn't just an amplifier, there is also a DAC onboard. So how does it
perform?

Let's Play Name That DAC!While the DAC is quite good, it a bit more of a mixed bag than
the outstanding amplifier section. Switching over from the unbalanced input,
there was a substantial jump in volume with the amplifier now running in
balanced mode off of the internal DAC. It took a little bit of tweaking to
ensure test conditions were fair and setup properly, but once everything was in
order, comparison tests with other DACs were fairly straightforward.

Comparing first to my reference Hugo 2, I found that the HDV
820's DAC was not as detailed or transparent as the Chord unit, but was still
actually quite detailed. Instruments had fairly natural sounding timbre to them,
but the Hugo 2 clearly performed better with more tonal nuance in the mids and
better control in the high frequencies. The HDV 820's internal DAC
occasionally had a little extra sharpness on a sibilant "S" here or there.
With the Hugo 2, the amp was sufficiently warm that I could really crank it up
and not worry about it.

Without direct comparison to a better source, you probably
wouldn't notice the difference. Still, I found it harder to sit for long
sessions with the onboard DAC, whereas it was much more difficult to get up and
walk away with the Hugo 2 plugged into the HDV 820's amplifier section.
However, the Hugo 2 costs as much as the HDV 820 itself, so perhaps comparing it
directly to the DAC alone isn't entirely fair. With that in mind, I also
compared it to the DAC section of a respectable DAP (the Acoustic Research
AR-M2, $1199) and two mid-priced DACs: the Audio-GD DAC-19 ($899) and the Chord
Mojo ($529).

Compared to the Acoustic Research AR-M2, the HDV
820's DAC
started looking much better. I noticed more presence and assertiveness, stage
depth, color, warmth and musicality from the HDV 820's DAC while using both
Amarra 4 Luxe and Roon off of my MacBook Pro. Comparing a 24-bit/96kHz version
of Buena Vista Social Club's self-titled album, music out of the AR-M2's
relatively good Burr-Brown DAC sounded a little more like a facsimile than the
real thing. It came off as somewhat plasticky in relation to the analog warmth
of the HDV 820.

Going up against with the Audio-GD DAC-19, proved to be an
interesting matchup. The DAC-19 remains my standard for a good sounding, sub
$1000 headphone DAC, using an excellent implementation of the Burr-Brown
PCM1704UK R2R chip. It runs a little on the warm and gooey side, but sounds very
analog, and is quite detailed. Head-to-head, the HDV 820's digital section
fell a little short, as the Audio-GD offered a better sense of depth and analog
resolution to the individual sounds. The DAC-19 also offered a bit better
impact, dynamic thrust and a better sense of connectedness with the natural PRAT
(pace, rhythm and timing) of the song. Switching back and forth, there seemed to
be a very slight sluggish haze on the HDV 820's DAC, but overall it wasn't
terribly far behind. All of the differences were small.

Last but not least, I compared the HDV 820 directly against
the Chord Mojo. The Mojo is a sensational and immensely popular mid-priced DAC,
and represents one of the very best values in all of high-end audio. Matched up
against the HDV 820, I had a very difficult time hearing any discernable
differences between the DACs, at all. In fact, I couldn't find one single
consistent difference to call out in the review. To me, they sound nearly
identical. Overall, that's not a bad place to be for the HDV 820, as I feel
like the Mojo is an excellent piece of gear and I recommend it frequently. It
scales well, and I've used it with amps that are as good or better than the
HDV 820 on many occasions.

So while the DAC section may not be as much of a standout as
the amplifier, it is still more than respectable, comparing favorably to one of
the most popular DACs on the market today. Just understand that what you're
getting is more like a $2000+ amplifier and a $500ish DAC than an even split, if
that's what you were expecting. It will get the job done very well if it is
your only piece, but there is substantial room to scale up by adding a better
digital component like the Hugo 2 or the Schiit Yggdrasil. It also means the HDV
820 is a piece that can grow with your setup over time.

Final ThoughtsSo where does the HDV 820 fit within the headphone amplifier
landscape? I would say it slots in pretty comfortably for a warm all-rounder at
its price point. Compared to other recently reviewed pieces, I would say it isn't as thunderously dynamic or incisive as the powerhouse
Wells Milo (reviewed
here); and it isn't quite as airy, open and expansive as the recently
reviewed Rogue RH-5. But I would call it the most lush and musical option of the
three. In many ways the three are equally good, albeit markedly different
sounding amplifiers.

Given that the HDV 820 also includes preamp outs (the RH-5
does as well) and an onboard DAC, it certainly has a lot going for it from a
value perspective. One should note that it is a little bit colored on the warm
side when considering it as a total reference piece, and professional users may
want to lean toward the slightly more neutral Rogue RH-5 as a benchmark for
their mixing decisions. However, audiophiles looking to expand the musical range
of their HD800 will definitely want to give this one a look.

In my opinion, the balance offered by the added warmth here
ensures that the HD800 will likely be the only headphone you'll ever need.
That being said, the HDV 820 is versatile enough to offer top-flight synergy
with many other headphones too. Particularly offerings from MrSpeakers, which
will garner added fullness from the Sennheiser's amp section and take full
advantage of its excellent depth layering; and Fostex/Denon biocellulose
variants, which will benefit from the HDV 820's warm lower midrange
presentation and well-behaved treble.

At
the end of the day, I think Sennheiser has introduced a real gem here. It's a
fun sounding piece of equipment and I feel like this is a piece I'll be
recommending frequently in the near future. If you're looking for a slightly
warm and lush do-it-all piece that can add some musicality while keeping pace
with your most resolving headphones, definitely give this one an audition.